The invention relates to a sample-holding element for a liquid sample, an analysis device set for simultaneous analysis of three or more chemical and physical parameters of liquids that comprises an analysis apparatus designed as a hand-held device and the sample-holding element for the liquid sample, the use of the set, and a method that is implemented using the analysis apparatus and the sample-holding element.
The prior art knows measuring devices that can be used to measure or check various parameters of cooling lubricants. Accordingly, refractometers for determination of the refractive index of the cooling lubricant are known. In the case of water-mixed cooling lubricants, the mixing ratio can be deduced from the refractive index. Moreover, measuring devices for determination of the electric conductivity are known, in which the resistance is determined via a certain measuring section. Measuring devices for determination of the pH value of the cooling lubricants are available as well. Essentially, two types of pH-measuring devices are used in this context: pH meters with electrode and optochemical pH measuring devices.
Moreover, there are measuring devices available that can determine different parameters after prior selection of the measuring parameter.
Accordingly, DE 10 2010 028 319 discloses a method for controlling the concentration of water-mixed cooling lubricants, in which a refractometer is used for determination of the refractive index of the cooling lubricant and the electrical conductivity is recorded through a resistance measurement, with its reciprocal resulting in the conductivity. Moreover, the temperature of the cooling lubricants is monitored in order to take into account the changes of the data arising from temperature fluctuations. The measured parameters are used to draw conclusions concerning the composition of the cooling lubricant and the composition is adapted in case of need.
DE 696 34 490 T2 discloses a disc-shaped microsystem platform with two flat planar surfaces as sample-holding element for a liquid sample. The disc-shaped microsystem platform comprises input ports for a liquid sample, liquid micro-channels, reaction and detection chambers, wherein multiple measuring points are provided on the disc for analysis of the liquid sample. The measurements that can be done comprise luminescence measurements and refractive index measurements as well as electrochemical detection methods. The corresponding analysis device is fitted, similar to a CD player, with elements for rotating and reading the disc-shaped microsystem platform for controlling the functions. After application of the analyte to be tested into the input ports, the microsystem platform is inserted into the CD player device, wherein the liquid transport through the micro-channels on the disc takes place by means of centripetal acceleration in the CD player device and by selective activation of valves on the disc. The results of the analysis can be saved and/or displayed immediately to the user.
A sample cassette with channels and chambers that can comprise electrodes and detection windows for optical measurements is known from US 2011/201099 A1. Reagents such as binding reagents, detectable markers, sample preparation reagents, washing solutions, buffers, etc., in liquid or solid form or on the surface of fixed immobilised phase carriers can be present in the chambers. The corresponding analysis apparatus, which is not provided as a hand-held device, comprises appropriate detectors and means for accommodating the cassette and for positioning the cassette as well as electrical systems for contacting the electrodes of the cassette as well as control systems for detecting, processing, and saving the signals of the detectors for the intended measurements. For luminescence measurements, the analysis apparatus comprises an area that is closed in light-tight manner. For accommodation and positioning of the sample-holding element, the analysis apparatus comprises a cassette compartment that is mounted on rails via a guide sled in order to enable a motor-driven motion of the compartment into and out of the area that is closed in light-tight manner.
US 2013/330245 A1 describes a sample-holding element with channels and a detection chamber for optical measurements as well as electrodes at the fluid inlet for measurement of the resistance of the sample in order to signal sufficient immersion of the sample-holding element into the liquid to be tested during the sampling. For sampling, the sample-holding element is inserted into the corresponding analysis apparatus, which is designed as a hand-held device and can accommodate multiple sample-holding elements simultaneously for analysis of multiple parameters, and comprises corresponding optical analysis devices, etc. During the sampling, a liquid sample is drawn into the sample-holding element by a pump of the analysis device.
Based on said prior art, it is the object of the present invention to devise an improved device by means of which a liquid—such as a cooling lubricant—can be prepared with minimised sample volume needs for measurement of the concentration of the liquid or its components and for measurement or determination of multiple further parameters such as the refractive index and the temperature and, optionally, even further parameters that are characteristic of the nature of the fluid, while keeping the handling as simple as possible.